Viewing: github-redirect.dependabot.com

Repository navigation

More items

Blame

History

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

#ifdef _Py_TIER2

* This file contains the support code for CPython's uops optimizer.

* It also performs some simple optimizations.

* It performs a traditional data-flow analysis[1] over the trace of uops.

* Using the information gained, it chooses to emit, or skip certain instructions

* if possible.

* [1] For information on data-flow analysis, please see

* https://clang.llvm.org/docs/DataFlowAnalysisIntro.html

* */

#include "Python.h"

#include "opcode.h"

#include "pycore_dict.h"

#include "pycore_interp.h"

#include "pycore_opcode_metadata.h"

#include "pycore_opcode_utils.h"

#include "pycore_pystate.h" // _PyInterpreterState_GET()

#include "pycore_uop_metadata.h"

#include "pycore_dict.h"

#include "pycore_long.h"

#include "pycore_optimizer.h"

#include "pycore_object.h"

#include "pycore_dict.h"

#include "pycore_function.h"

#include "pycore_uop_metadata.h"

#include "pycore_uop_ids.h"

#include "pycore_range.h"

#include <stdarg.h>

#include <stdbool.h>

#include <stdint.h>

#include <stddef.h>

#ifdef Py_DEBUG

extern const char *_PyUOpName(int index);

extern void _PyUOpPrint(const _PyUOpInstruction *uop);

static const char *const DEBUG_ENV = "PYTHON_OPT_DEBUG";

static inline int get_lltrace(void) {

char *uop_debug = Py_GETENV(DEBUG_ENV);

int lltrace = 0;

if (uop_debug != NULL && *uop_debug >= '0') {

lltrace = *uop_debug - '0'; // TODO: Parse an int and all that

}

return lltrace;

}

#define DPRINTF(level, ...) \

if (get_lltrace() >= (level)) { printf(__VA_ARGS__); }

#else

#define DPRINTF(level, ...)

#endif

static inline bool

op_is_end(uint32_t opcode)

{

return opcode == _EXIT_TRACE || opcode == _JUMP_TO_TOP;

}

static int

get_mutations(PyObject* dict) {

assert(PyDict_CheckExact(dict));

PyDictObject *d = (PyDictObject *)dict;

return (d->ma_version_tag >> DICT_MAX_WATCHERS) & ((1 << DICT_WATCHED_MUTATION_BITS)-1);

}

static void

increment_mutations(PyObject* dict) {

assert(PyDict_CheckExact(dict));

PyDictObject *d = (PyDictObject *)dict;

d->ma_version_tag += (1 << DICT_MAX_WATCHERS);

}

/* The first two dict watcher IDs are reserved for CPython,

* so we don't need to check that they haven't been used */

#define BUILTINS_WATCHER_ID 0

#define GLOBALS_WATCHER_ID 1

static int

globals_watcher_callback(PyDict_WatchEvent event, PyObject* dict,

PyObject* key, PyObject* new_value)

{

RARE_EVENT_STAT_INC(watched_globals_modification);

assert(get_mutations(dict) < _Py_MAX_ALLOWED_GLOBALS_MODIFICATIONS);

_Py_Executors_InvalidateDependency(_PyInterpreterState_GET(), dict, 1);

increment_mutations(dict);

PyDict_Unwatch(GLOBALS_WATCHER_ID, dict);

return 0;

}

static PyObject *

convert_global_to_const(_PyUOpInstruction *inst, PyObject *obj)

{

assert(inst->opcode == _LOAD_GLOBAL_MODULE || inst->opcode == _LOAD_GLOBAL_BUILTINS || inst->opcode == _LOAD_ATTR_MODULE);

assert(PyDict_CheckExact(obj));

PyDictObject *dict = (PyDictObject *)obj;

assert(dict->ma_keys->dk_kind == DICT_KEYS_UNICODE);

PyDictUnicodeEntry *entries = DK_UNICODE_ENTRIES(dict->ma_keys);

assert(inst->operand <= UINT16_MAX);

if ((int)inst->operand >= dict->ma_keys->dk_nentries) {

return NULL;

}

PyObject *res = entries[inst->operand].me_value;

if (res == NULL) {

return NULL;

}

if (_Py_IsImmortal(res)) {

inst->opcode = (inst->oparg & 1) ? _LOAD_CONST_INLINE_BORROW_WITH_NULL : _LOAD_CONST_INLINE_BORROW;

}

else {

inst->opcode = (inst->oparg & 1) ? _LOAD_CONST_INLINE_WITH_NULL : _LOAD_CONST_INLINE;

}

inst->operand = (uint64_t)res;

return res;

}

static int

incorrect_keys(_PyUOpInstruction *inst, PyObject *obj)

{

if (!PyDict_CheckExact(obj)) {

return 1;

}

PyDictObject *dict = (PyDictObject *)obj;

if (dict->ma_keys->dk_version != inst->operand) {

return 1;

}

return 0;

}

/* Returns 1 if successfully optimized

* 0 if the trace is not suitable for optimization (yet)

* -1 if there was an error. */

static int

remove_globals(_PyInterpreterFrame *frame, _PyUOpInstruction *buffer,

int buffer_size, _PyBloomFilter *dependencies)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

PyObject *builtins = frame->f_builtins;

if (builtins != interp->builtins) {

OPT_STAT_INC(remove_globals_builtins_changed);

return 1;

}

PyObject *globals = frame->f_globals;

PyFunctionObject *function = (PyFunctionObject *)frame->f_funcobj;

assert(PyFunction_Check(function));

assert(function->func_builtins == builtins);

assert(function->func_globals == globals);

uint32_t function_version = _PyFunction_GetVersionForCurrentState(function);

/* In order to treat globals as constants, we need to

* know that the globals dict is the one we expected, and

* that it hasn't changed

* In order to treat builtins as constants, we need to

* know that the builtins dict is the one we expected, and

* that it hasn't changed and that the global dictionary's

* keys have not changed */

/* These values represent stacks of booleans (one bool per bit).

* Pushing a frame shifts left, popping a frame shifts right. */

uint32_t function_checked = 0;

uint32_t builtins_watched = 0;

uint32_t globals_watched = 0;

uint32_t prechecked_function_version = 0;

if (interp->dict_state.watchers[GLOBALS_WATCHER_ID] == NULL) {

interp->dict_state.watchers[GLOBALS_WATCHER_ID] = globals_watcher_callback;

}

for (int pc = 0; pc < buffer_size; pc++) {

_PyUOpInstruction *inst = &buffer[pc];

int opcode = inst->opcode;

switch(opcode) {

case _GUARD_BUILTINS_VERSION:

if (incorrect_keys(inst, builtins)) {

OPT_STAT_INC(remove_globals_incorrect_keys);

return 0;

}

if (interp->rare_events.builtin_dict >= _Py_MAX_ALLOWED_BUILTINS_MODIFICATIONS) {

continue;

}

if ((builtins_watched & 1) == 0) {

PyDict_Watch(BUILTINS_WATCHER_ID, builtins);

builtins_watched |= 1;

}

if (function_checked & 1) {

buffer[pc].opcode = NOP;

}

else {

buffer[pc].opcode = _CHECK_FUNCTION;

buffer[pc].operand = function_version;

function_checked |= 1;

}

break;

case _GUARD_GLOBALS_VERSION:

if (incorrect_keys(inst, globals)) {

OPT_STAT_INC(remove_globals_incorrect_keys);

return 0;

}

uint64_t watched_mutations = get_mutations(globals);

if (watched_mutations >= _Py_MAX_ALLOWED_GLOBALS_MODIFICATIONS) {

continue;

}

if ((globals_watched & 1) == 0) {

PyDict_Watch(GLOBALS_WATCHER_ID, globals);

_Py_BloomFilter_Add(dependencies, globals);

globals_watched |= 1;

}

if (function_checked & 1) {

buffer[pc].opcode = NOP;

}

else {

buffer[pc].opcode = _CHECK_FUNCTION;

buffer[pc].operand = function_version;

function_checked |= 1;

}

break;

case _LOAD_GLOBAL_BUILTINS:

if (function_checked & globals_watched & builtins_watched & 1) {

convert_global_to_const(inst, builtins);

}

break;

case _LOAD_GLOBAL_MODULE:

if (function_checked & globals_watched & 1) {

convert_global_to_const(inst, globals);

}

break;

case _PUSH_FRAME:

{

builtins_watched <<= 1;

globals_watched <<= 1;

function_checked <<= 1;

uint64_t operand = buffer[pc].operand;

if (operand == 0 || (operand & 1)) {

// It's either a code object or NULL, so bail

return 1;

}

PyFunctionObject *func = (PyFunctionObject *)operand;

if (func == NULL) {

return 1;

}

assert(PyFunction_Check(func));

function_version = func->func_version;

if (prechecked_function_version == function_version) {

function_checked |= 1;

}

prechecked_function_version = 0;

globals = func->func_globals;

builtins = func->func_builtins;

if (builtins != interp->builtins) {

OPT_STAT_INC(remove_globals_builtins_changed);

return 1;

}

break;

}

case _POP_FRAME:

{

builtins_watched >>= 1;

globals_watched >>= 1;

function_checked >>= 1;

uint64_t operand = buffer[pc].operand;

if (operand == 0 || (operand & 1)) {

// It's either a code object or NULL, so bail

return 1;

}

PyFunctionObject *func = (PyFunctionObject *)operand;

if (func == NULL) {

return 1;

}

assert(PyFunction_Check(func));

function_version = func->func_version;

globals = func->func_globals;

builtins = func->func_builtins;

break;

}

case _CHECK_FUNCTION_EXACT_ARGS:

prechecked_function_version = (uint32_t)buffer[pc].operand;

break;

default:

if (op_is_end(opcode)) {

return 1;

}

break;

}

return 0;

}

#define STACK_LEVEL() ((int)(stack_pointer - ctx->frame->stack))

#define GETLOCAL(idx) ((ctx->frame->locals[idx]))

#define REPLACE_OP(INST, OP, ARG, OPERAND) \

INST->opcode = OP; \

INST->oparg = ARG; \

INST->operand = OPERAND;

#define OUT_OF_SPACE_IF_NULL(EXPR) \

do { \

if ((EXPR) == NULL) { \

goto out_of_space; \

} \

} while (0);

#define _LOAD_ATTR_NOT_NULL \

do { \

OUT_OF_SPACE_IF_NULL(attr = _Py_uop_sym_new_not_null(ctx)); \

OUT_OF_SPACE_IF_NULL(null = _Py_uop_sym_new_null(ctx)); \

} while (0);

/* Shortened forms for convenience, used in optimizer_bytecodes.c */

#define sym_is_not_null _Py_uop_sym_is_not_null

#define sym_is_const _Py_uop_sym_is_const

#define sym_get_const _Py_uop_sym_get_const

#define sym_new_unknown _Py_uop_sym_new_unknown

#define sym_new_not_null _Py_uop_sym_new_not_null

#define sym_new_type _Py_uop_sym_new_type

#define sym_is_null _Py_uop_sym_is_null

#define sym_new_const _Py_uop_sym_new_const

#define sym_new_null _Py_uop_sym_new_null

#define sym_has_type _Py_uop_sym_has_type

#define sym_get_type _Py_uop_sym_get_type

#define sym_matches_type _Py_uop_sym_matches_type

#define sym_set_null _Py_uop_sym_set_null

#define sym_set_non_null _Py_uop_sym_set_non_null

#define sym_set_type _Py_uop_sym_set_type

#define sym_set_const _Py_uop_sym_set_const

#define sym_is_bottom _Py_uop_sym_is_bottom

#define sym_truthiness _Py_uop_sym_truthiness

#define frame_new _Py_uop_frame_new

#define frame_pop _Py_uop_frame_pop

static int

optimize_to_bool(

_PyUOpInstruction *this_instr,

_Py_UOpsContext *ctx,

_Py_UopsSymbol *value,

_Py_UopsSymbol **result_ptr)

{

if (sym_matches_type(value, &PyBool_Type)) {

REPLACE_OP(this_instr, _NOP, 0, 0);

*result_ptr = value;

return 1;

}

int truthiness = sym_truthiness(value);

if (truthiness >= 0) {

PyObject *load = truthiness ? Py_True : Py_False;

REPLACE_OP(this_instr, _POP_TOP_LOAD_CONST_INLINE_BORROW, 0, (uintptr_t)load);

*result_ptr = sym_new_const(ctx, load);

return 1;

}

return 0;

}

static void

eliminate_pop_guard(_PyUOpInstruction *this_instr, bool exit)

{

REPLACE_OP(this_instr, _POP_TOP, 0, 0);

if (exit) {

REPLACE_OP((this_instr+1), _EXIT_TRACE, 0, 0);

this_instr[1].target = this_instr->target;

}

/* _PUSH_FRAME/_POP_FRAME's operand can be 0, a PyFunctionObject *, or a

* PyCodeObject *. Retrieve the code object if possible.

static PyCodeObject *

get_code(_PyUOpInstruction *op)

{

assert(op->opcode == _PUSH_FRAME || op->opcode == _POP_FRAME || op->opcode == _RETURN_GENERATOR);

PyCodeObject *co = NULL;

uint64_t operand = op->operand;

if (operand == 0) {

return NULL;

}

if (operand & 1) {

co = (PyCodeObject *)(operand & ~1);

}

else {

PyFunctionObject *func = (PyFunctionObject *)operand;

assert(PyFunction_Check(func));

co = (PyCodeObject *)func->func_code;

}

assert(PyCode_Check(co));

return co;

}

/* 1 for success, 0 for not ready, cannot error at the moment. */

static int

optimize_uops(

PyCodeObject *co,

_PyUOpInstruction *trace,

int trace_len,

int curr_stacklen,

_PyBloomFilter *dependencies

)

{

_Py_UOpsContext context;

_Py_UOpsContext *ctx = &context;

uint32_t opcode = UINT16_MAX;

int curr_space = 0;

int max_space = 0;

_PyUOpInstruction *first_valid_check_stack = NULL;

_PyUOpInstruction *corresponding_check_stack = NULL;

if (_Py_uop_abstractcontext_init(ctx) < 0) {

goto out_of_space;

}

_Py_UOpsAbstractFrame *frame = _Py_uop_frame_new(ctx, co, curr_stacklen, NULL, 0);

if (frame == NULL) {

return -1;

}

ctx->curr_frame_depth++;

ctx->frame = frame;

_PyUOpInstruction *this_instr = NULL;

for (int i = 0; i < trace_len; i++) {

this_instr = &trace[i];

int oparg = this_instr->oparg;

opcode = this_instr->opcode;

_Py_UopsSymbol **stack_pointer = ctx->frame->stack_pointer;

#ifdef Py_DEBUG

if (get_lltrace() >= 3) {

printf("%4d abs: ", (int)(this_instr - trace));

_PyUOpPrint(this_instr);

printf(" ");

}

#endif

switch (opcode) {

#include "optimizer_cases.c.h"

default:

DPRINTF(1, "\nUnknown opcode in abstract interpreter\n");

Py_UNREACHABLE();

}

assert(ctx->frame != NULL);

DPRINTF(3, " stack_level %d\n", STACK_LEVEL());

ctx->frame->stack_pointer = stack_pointer;

assert(STACK_LEVEL() >= 0);

}

Py_UNREACHABLE();

out_of_space:

DPRINTF(3, "\n");

DPRINTF(1, "Out of space in abstract interpreter\n");

goto done;

error:

DPRINTF(3, "\n");

DPRINTF(1, "Encountered error in abstract interpreter\n");

if (opcode <= MAX_UOP_ID) {

OPT_ERROR_IN_OPCODE(opcode);

}

_Py_uop_abstractcontext_fini(ctx);

return -1;

hit_bottom:

// Attempted to push a "bottom" (contradition) symbol onto the stack.

// This means that the abstract interpreter has hit unreachable code.

// We *could* generate an _EXIT_TRACE or _FATAL_ERROR here, but hitting

// bottom indicates type instability, so we are probably better off

// retrying later.

DPRINTF(3, "\n");

DPRINTF(1, "Hit bottom in abstract interpreter\n");

_Py_uop_abstractcontext_fini(ctx);

return 0;

done:

/* Either reached the end or cannot optimize further, but there

* would be no benefit in retrying later */

_Py_uop_abstractcontext_fini(ctx);

if (first_valid_check_stack != NULL) {

assert(first_valid_check_stack->opcode == _CHECK_STACK_SPACE);

assert(max_space > 0);

assert(max_space <= INT_MAX);

assert(max_space <= INT32_MAX);

first_valid_check_stack->opcode = _CHECK_STACK_SPACE_OPERAND;

first_valid_check_stack->operand = max_space;

}

return trace_len;

}

static int

remove_unneeded_uops(_PyUOpInstruction *buffer, int buffer_size)

{

/* Remove _SET_IP and _CHECK_VALIDITY where possible.

* _SET_IP is needed if the following instruction escapes or

* could error. _CHECK_VALIDITY is needed if the previous

* instruction could have escaped. */

int last_set_ip = -1;

bool may_have_escaped = true;

for (int pc = 0; pc < buffer_size; pc++) {

int opcode = buffer[pc].opcode;

switch (opcode) {

case _START_EXECUTOR:

may_have_escaped = false;

break;

case _SET_IP:

buffer[pc].opcode = _NOP;

last_set_ip = pc;

break;

case _CHECK_VALIDITY:

if (may_have_escaped) {

may_have_escaped = false;

}

else {

buffer[pc].opcode = _NOP;

}

break;

case _CHECK_VALIDITY_AND_SET_IP:

if (may_have_escaped) {

may_have_escaped = false;

buffer[pc].opcode = _CHECK_VALIDITY;

}

else {

buffer[pc].opcode = _NOP;

}

last_set_ip = pc;

break;

case _POP_TOP:

{

_PyUOpInstruction *last = &buffer[pc-1];

while (last->opcode == _NOP) {

last--;

}

if (last->opcode == _LOAD_CONST_INLINE ||

last->opcode == _LOAD_CONST_INLINE_BORROW ||

last->opcode == _LOAD_FAST ||

last->opcode == _COPY

) {

last->opcode = _NOP;

buffer[pc].opcode = _NOP;

}

if (last->opcode == _REPLACE_WITH_TRUE) {

last->opcode = _NOP;

}

break;

}

case _JUMP_TO_TOP:

case _EXIT_TRACE:

return pc + 1;

default:

{

/* _PUSH_FRAME doesn't escape or error, but it

* does need the IP for the return address */

bool needs_ip = opcode == _PUSH_FRAME;

if (_PyUop_Flags[opcode] & HAS_ESCAPES_FLAG) {

needs_ip = true;

may_have_escaped = true;

}

if (needs_ip && last_set_ip >= 0) {

if (buffer[last_set_ip].opcode == _CHECK_VALIDITY) {

buffer[last_set_ip].opcode = _CHECK_VALIDITY_AND_SET_IP;

}

else {

assert(buffer[last_set_ip].opcode == _NOP);

buffer[last_set_ip].opcode = _SET_IP;

}

last_set_ip = -1;

}

Py_UNREACHABLE();

}

// 0 - failure, no error raised, just fall back to Tier 1

// -1 - failure, and raise error

// > 0 - length of optimized trace

int

_Py_uop_analyze_and_optimize(

_PyInterpreterFrame *frame,

_PyUOpInstruction *buffer,

int length,

int curr_stacklen,

_PyBloomFilter *dependencies

)

{

OPT_STAT_INC(optimizer_attempts);

int err = remove_globals(frame, buffer, length, dependencies);

if (err <= 0) {

return err;

}

length = optimize_uops(

_PyFrame_GetCode(frame), buffer,

length, curr_stacklen, dependencies);

if (length <= 0) {

return length;

}

length = remove_unneeded_uops(buffer, length);

assert(length > 0);

OPT_STAT_INC(optimizer_successes);

return length;

}

#endif /* _Py_TIER2 */

Terms
Privacy
Security
Status
Community
Docs
Contact
Manage cookies
Do not share my personal information

Navigation Menu

Repository navigation

Files

optimizer_analysis.c

optimizer_analysis.c

Navigation Menu

Repository navigation

FilesExpand file tree

Breadcrumbs

optimizer_analysis.c

Latest commit

History

Breadcrumbs

optimizer_analysis.c

File metadata and controls

Footer

Footer navigation

Files